# NTSB WPR24LA262: Hiller UH-12E, N3375T, Bonners Ferry, ID, July 24, 2024 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: July 24, 2024, 07:30 local (14:30 UTC) - Place: Bonners Ferry, ID · Lakeshore - Coordinates: 48.838352, -116.56743 - Nearby events: https://openairdocs.org/map.md?lat=48.8384&lon=-116.5674&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 194811 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR24LA262 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/194811/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=194811 - Page: https://openairdocs.org/ntsb/WPR24LA262 ## Probable cause The pilot’s improper selection of a landing site, which resulted in a main rotor strike. Contributing to the accident was the pilot’s improper performance planning and altitude selection over water, which resulted in an rpm droop. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Hiller UH-12E, 7 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=4360122), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Performance/control parameters: powerplant parameters](https://openairdocs.org/ntsb-findings/01062050): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Hiller UH-12E, 1 case](https://openairdocs.org/ntsb-findings/01062050/cases.md?model=4360122), [All aircraft, 81 cases](https://openairdocs.org/ntsb-findings/01062050/cases.md) - [Performance/control parameters: prop/rotor parameters](https://openairdocs.org/ntsb-findings/01062052): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Hiller UH-12E, 2 cases](https://openairdocs.org/ntsb-findings/01062052/cases.md?model=4360122), [All aircraft, 182 cases](https://openairdocs.org/ntsb-findings/01062052/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Hiller UH-12E, 7 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=4360122), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) ## Analysis The pilot of the helicopter reported that with two passengers aboard, he approached a mountain lake to a hover above the water and saw the engine and rotor speed decrease to the green arc of the engine and rotor tachometer. He maneuvered the helicopter to the shore, and with the engine and rotor continuing to droop, he landed on some “substantially sized granite rocks” where the skids became lodged in the rocks. The helicopter then tipped forward and the main rotor blades impacted the rocks, which resulted in substantial damage to the main rotor and fuselage. The pilot reported there were no mechanical malfunctions or failures with the helicopter that would have precluded normal operation. The pilot added that he did not verify the performance capability for an in-ground effect or a hover out of ground effect over water. The Helicopter Flying Handbook, FAA-H-8083-21B, states, “When hovering over surfaces as tall grass, trees, bushes, rough terrain, and water, maximum ground effect is reduced.” ## Aircraft - Registration: [N3375T](https://openairdocs.org/aircraft/N3375T), registered now, S/N 5237 (OpenAirDocs) - Reported make and model: HILLER UH-12E - Registry model: [Hiller UH-12E](https://openairdocs.org/model/hiller-uh-12e) (registry code 4360122) (OpenAirDocs) - Category: Helicopter - Serial number: 5237 - Year built: 2001 - Airframe hours: 425.9 - Engines: Lycoming VO540C2A 305 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, October 24, 2023, 35 hours before - Departed: Priv, Bonners Ferry, ID - Airport: None - Equipment: ADS-B, Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 66; injuries: none; private; medical: class 3, without waivers/limitations; last flight review August 24, 2023; seat: center; restraint: 3-point; flight hours: 349 total, 272 in this make and model, 281 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 61 °F, dew point 41 °F - Altimeter: 30.06 inHg - Observed at: K65S, 13 nm away - METAR: K65S 241435Z AUTO 00000KT 10SM CLR 16/05 A3006 RMK AO2 ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20240724009899A](https://openairdocs.org/incident/20240724009899A), Jul 24, 2024: Hiller UH-12E, Big Fisher Lake, ID, Substantial damage. Helicopter was flown from bonners ferry, ID to Big Fisher Lake, ID. After arrival while hovering over water, pilot was unable to maintain hover. Moving over… ## Docket (2 files) The files NTSB released with the investigation on March 6, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=194811. 5.2 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 4.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17502878&FileExtension=pdf&FileName=N3375T%20NTSB%20accident%20report_Redacted-Rel.pdf - Photos for WPR24LA262 (item 2, PDF, 1 page, 493 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17633572&FileExtension=pdf&FileName=Photo%20for%20WPR24LA262%20_Redacted-Rel.pdf From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.